1. Field of the Invention
This invention relates to synergistic antimicrobial or biocidal compositions including an isothiazolone and one or more of known biocides for more effective and broader control of micro-organisms in various industrial systems and for household products, agricultural products, and biomedical products, etc. In particular, the present invention relates to the use of a composition of 2-n-octyl-4-isothiazolin-3-one (also known as 2-n-octyl-3-isothiazolone or 2-n-octylisothiazolone) with one or more of the following 21 compounds: 2-(hydroxymethyl)amino-2-methylpropanol; 2-(hydroxymethyl)aminoethanol; 5-bromo-5-nitro-1,3-dioxane; hexahydro-1,3,5-triethyl-s-triazine; .alpha.-benzoyl-.alpha.-chloroformaldoxime; benzylbromoacetate; p-chloro-m-xylenol; bis-(2-hydroxy-5-chlorophenyl)sulfide; p-tolyldiiodomethylsulfone; 3-iodo-2-propynylbutylcarbamate; 5-hydroxypoly(methyleneoxy)-methyl-1-aza-3,7-dioxabicyclo(3,3,0)octane; dipropylamine ether; dodecylamine; N-(hydroxymethyl)-N'-(1,3-di(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl)-N' -(hydroxymethyl)urea; 1-(3-chloroallyl)-3,5,7-triaza-1-azoniaadamantane chloride; 1,2-dibromo-2,4-dicyanobutane; N,N-dimethyl-N'-phenyl-N'-(fluorodichloromethylthio)sulfamide; N,N'-di(hydroxymethyl)-5,5'-dimethylhydantoin; 2-bromo-2-nitropropanediol; methylene-bis-thiocyanate; and 2,4-dichlorobenzyl alcohol.
2. Prior Art
The isothiazolones are described in U.S. Pat. Nos. 3,761,488; 4,105,431; 4,252,694; 4,265,899 and 4,279,762, and elsewhere. The 2-n-octyl-4-isothiazolin-3-one (octhilinone) is a superior fungicide with relatively lower activity against Gram-negative bacteria. The low activity against Gram negative bacteria has limited its uses in industrial systems where both bacteria and fungi are fouling the systems. To control these situations requires a higher concentration of octhilinone, which increases the cost of the treatment. Therefore, it is useful to find compositions which are more effective and exert broader control.
It has been discovered that compositions formed from 2-n-octyl-4-isothiazolin-3-one and one or more of the 21 specified compounds (supra) within specified range of ratios unexpectedly afforded synergistic antimicrobial activity against a wide range of microorganisms. The synergy in which the disruptive action on the organisms by the two compounds together is greater than the sum of both compounds taken alone does not arise from the expected activity of the components or from the expected improvement in activity. As a result of the synergy, the effective dose which can be lowered is not only more economical but also increases safety margin. The synergistic compositions provide more effective and broader control of microorganisms in a number of industrial systems.
It is the principal object of this invention to provide the use of synergistic compositions which overcome the disadvantages of the known biocidal compositions.
Important applications of the synergistic antimicrobial compositions of the present invention include but are not limited to: inhibiting the growth of bacteria and fungi in aqueous paints and coatings, adhesives, sealants, latex emulsions, and joint cements; preserving wood; preserving cutting fluids, controlling slime-producing bacteria and fungi in pulp and papermills and cooling towers; as a spray or dip treatment for textiles and leather to prevent mold growth; protecting paint films, especially exterior paints, from attack by fungi which occurs during weathering of the paint film; protecting processing equipment from slime deposits during manufacture of cane and beet sugar; preventing microorganism buildup and deposits in air washer or scrubber systems and in industrial fresh water supply systems; preserving fuel; controlling microorganisms contamination and deposits in oil field drilling fluids and muds, and in secondary petroleum recovery processes; preventing bacterial and fungal growth in paper coatings and coating processes; controlling bacterial and fungal growth and deposits during the manufacture of various specialty boards, e.g., carboard and particle board; preventing sap stain discoloration on freshly cut wood of various kinds; controlling bacterial and fungal growth in clay and pigment slurries of various types; as a hard surface disinfectant to prevent growth of bacteria and fungi on walls, floors, etc.; as a preservative for cosmetic and toiletry raw materials, floor polishes, fabric softeners, household and industrial cleaners; in swimming pools to prevent algae growth; inhibiting the growth of harmful bacteria, yeasts, fungi on plants, trees, fruits, seeds, or soil; preserving agricultural formulations, electrodeposition systems, diagnostic and reagent products, medical devices; protecting animal dip compositions against the buildup of microorganisms, and in photoprocessing to prevent buildup of microorganisms, and the like.
The synergistic compositions of the invention may be added separately to an industrial system or may be formulated as a simple mixture comprising its essential ingredients, and if desired a suitable carrier or solvent, or as an aqueous emulsion or dispersion.